Reports that David Miliband spent two hours at the Foreign Office checking the record of his possible involvement in decisions on the interrogation of UK nationals overseas is interesting on a number of levels. If nothing else, it confirms that this formidable figure has not been able to brush off the penumbra of allegations that hang over him and the last government.

I have no doubt that Miliband abhors torture, and would never, to take the legal formulation, wish to be complicit in it. The issue is not a propensity to embrace the dark side, as Dick Cheney once described it, but a question of judgment and baggage.

When he became foreign secretary in June 2007, there were already allegations about possible British involvement in overseas torture by other countries' intelligence services. At that point he could have announced that he wanted to establish a proper inquiry. He didn't do that – and was a senior member of a government that later actively resisted calls for an inquiry. That is not to say he was idle throughout this period; he seems to have put considerable energy into defending a number of claims in the English courts relating to torture against his department.

The Foreign Office resisted claims that the government was obliged to disclose evidence it held that US and Moroccan authorities engaged in torture or rendition. Miliband resisted claims that the UK was under any obligation under international law to assist foreign courts and tribunals in ensuring that torture evidence was not admitted.

His approach is set out in a letter of 24 April 2008 to the lawyers for Binyam Mohamed – for whom I acted at that stage of the proceedings. I found the tone of the letter surprising when I first saw it, and it reads even more unhappily today. No doubt he was entitled to make those arguments, but was it a wise choice? Was it wise to defend cases in circumstances where he had seen documents that showed that MI5 officers knew a British resident had been tortured yet continued to provide questions via the CIA? Miliband fought and lost a series of cases that can and should have been resolved by other means. That raises a question of judgment.

The evidence now available, much of which emerged from those cases, indicates a colourable case in support of claims that Britain was complicit in torture after 9/11. Responsibility for such complicity could lie at the feet of rogue intelligence officers, who may have been off on a frolic. Or it could lie with those ministers who signed off on the relevant guidance, assuming they did.

Many would not be surprised if all roads led to Tony Blair (who described Guantánamo as "understandable" in his memoir). The truth is a matter for the forthcoming judicial inquiry. In the meantime it is not unusual to hear the suggestion that Miliband's actions may have been motivated in part by a desire to protect the reputation of his colleagues. That raises an issue of political baggage.

If this was the only baggage, he might not be hampered. But it's not. His attitude to the Iraq war is equally unhappy, invoking the refrain that "if I knew then what I know now I would have voted against". This recognises that the war was the wrong decision but falls well short of an expression of regret.

Miliband is a man of great ability. He would have earned considerable respect if he had said sorry for the war, and if he had announced a judicial inquiry into allegations of torture, as the new government has done. By now it may be too late. These judgment calls and the surrounding baggage may cost him the Labour leadership. If they do not, he should act promptly by drawing a real line so as to prevent the past from gumming up his prospects.